I've been monkeying around with Calibre, trying to fix some ebooks for my Kindle so that the TOC, Chapter Markers, or both (depending on the ebook) are set up properly. However, I'm encountering problems. First, some ebooks don't say "Chapter" or what have you at the start of chapters. Second, if Calibre converts the ebook to EPUB so that I can edit it to discover what the tags are at chapter headings, the tags are all CSS tags that Calibre created which doesn't help me at all.

What can I do to get specific help with these files? I have a suspicion that if I said "here, I bought this on Amazon, broke the DRM and am posting it here so ppl can help me fix it" that I'd be in deep... stuff.

So what do I do? Can I ask for specific help only if it's a public domain book?

Examples are: I have Star Trek: New Frontier which I bought from Amazon but has really weird chapter breaks such that Calibre only detects half of them; I also have The Wonderful Wizard of Oz from Project Gutenberg (for free), but the chapter numbers and subtitles are on the same line with no "Chapter #" text to alert calibre to put a marker there. This would especially be bad if I acquired the entire Oz set on one volume at some point.

Not sure which Calibre settings you're using as well to detect chapters - you can try enabling chapter markup under Heuristics to discover some of the chapters as well. Note this may change the look and feel of your document somewhat if it's successful - you can use extra_css and also Sigil as user_none noted to resolve that if it happens.